Apparatus and method for printing large thermoplastic parts during additive manufacturing

ABSTRACT

Embodiments of the present disclosure are drawn to additive manufacturing apparatus and methods. An exemplary additive manufacturing system may include an extruder, the extruder having an opening dimensioned to receive a material. The apparatus may also include an extruder output in fluid communication with the extruder, wherein the extruder output extends away from the extruder along a longitudinal axis. One or more heaters positioned along at least a portion of the extruder output may also be included, and, as the material passes through the extruder output, the one or more heaters may at least partially melt the material. The system may also include a gear pump in fluid communication with the extruder output for receiving the at least partially melted material, and a nozzle in fluid communication with the gear pump for depositing the at least partially melted material.

TECHNICAL FIELD

Aspects of the present disclosure relate to apparatus and methods forfabricating components. In some instances, aspects of the presentdisclosure relate to apparatus and methods for fabricating components(such as, e.g., automobile parts, medical devices, machine components,consumer products, etc.) via additive manufacturing techniques orprocesses, such as, e.g., three-dimensional (3D) printing manufacturingtechniques or processes.

BACKGROUND

Additive manufacturing techniques and processes generally involve thebuildup of one or more materials, e.g., layering, to make a net or nearnet shape (NNS) object, in contrast to subtractive manufacturingmethods. Though “additive manufacturing” is an industry standard term(ASTM F2792), additive manufacturing encompasses various manufacturingand prototyping techniques known under a variety of names, including,e.g., freeform fabrication, 3D printing, rapid prototyping/tooling, etc.Additive manufacturing techniques may be used to fabricate simple orcomplex components from a wide variety of materials. For example, afreestanding object may be fabricated from a computer-aided design (CAD)model.

A particular type of additive manufacturing is commonly known as 3Dprinting. One such process, commonly referred to as Fused DepositionModeling (FDM), or Fused Layer Modeling (FLM), comprises melting a thinlayer of thermoplastic material, and applying this material in layers toproduce a final part. This is commonly accomplished by passing acontinuous, thin filament of thermoplastic material through a heatednozzle, or by passing thermoplastic material into an extruder, with anattached nozzle, which melts the thermoplastic material and applies itto the structure being printed, building up the structure. The heatedmaterial is applied to the existing structure in layers, melting andfusing with the existing material to produce a solid finished part.

Three-dimensional printing of thermoplastic parts originated withrelatively small machines. These machines generally operated by feedinga thermoplastic filament through a heated nozzle, which then melted anddeposited the filament material in thin layers to build up a final shapeof the part. These machines also generally used a table, which whenheated sufficiently, was used to bond to the material being printed andsecure the material in place on the table during the printing process.It was necessary to keep the part being printed at a sufficiently hightemperature so that new material being printed would bond properly tothe existing structure (e.g., previously deposited layers of printedmaterial).

While this approach may produce small parts to the final net shape, theprocess may be relatively slow because it requires a thin filament andthin print layers to generate a relatively smooth outer surface; thus,manufacturing larger parts may be difficult with the aforementionedprocess.

To address this shortcoming, a system was developed to deposit materialat a higher speed, and in thicker layers (compared to net shape 3Dprinting), which yields a final part slightly larger in size than thefinal net shape (i.e., desired part). In a post-deposition process step,the printed part may be milled, or machined, to the final desired size.This process has become known as “near net shape.” This approach iswidely used for manufacturing large parts using 3D printing. Theadvantage is that it is substantially faster than the thin layerapproach.

In some examples, this system may use a small plastic extruder insteadof a pre-extruded filament to generate the melted print bead. In thissystem, the print head may move along a plane, depositing material ontoa heated table, which would move downward after each layer wascompleted. As with the filament system, the print environment mayrequire heat to maintain a minimum part temperature so that the newlyprinted material may adhere properly. Once the printing process iscomplete, the part may be allowed to cool. Once cooled, the part may beremoved and positioned onto a second machine, which may mill or machinethe cooled part to the final size and shape.

Although this process may work faster than the filament system, somedisadvantages have been encountered in the practice of theaforementioned process. Namely, the cost and/or complexity of the heatedtable and the heated print environment were undesirable. In the heatedprint environment, for example, keeping the part heated until printingwas complete and subsequently cooling the printed part may have resultedin internal stresses being introduced with the printed part, which wereunfavorable. Moreover, another disadvantage was that a separate printand trim machine was required, which required additional floor space.Moreover, when printed parts become relatively large, they may alsobecome heavy, which may make the process of moving them from one machineto another to trim them difficult. Lastly, since the cooled part mayshrink and warp from the original print size, the cooled part's outersurface may become somewhat indistinct, making it difficult and timeconsuming to orient the part properly when moved to the trim machine.

SUMMARY

Aspects of the present disclosure relate to, among other things, methodsand apparatus for fabricating components via additive manufacturing,e.g., 3D printing techniques. Each of the aspects disclosed herein mayinclude one or more of the features described in connection with any ofthe other disclosed aspects. Exemplary embodiments may be drawn to amachine that deposits material (e.g., prints) at ambient temperature,rather than in a heated environment, using a larger print bead at arelatively higher speed compared to traditional printing techniques.Unlike prior additive manufacturing systems, which incorporate devicesconfigured to raise the temperature of the surrounding air, embodimentsof the disclosure may omit such devices configured to increase thetemperature of the surrounding air. Prior systems generally print at aslower speed so that the printed material cools below a temperature atwhich proper bonding with an earlier-printed layer of material mayoccur. To counteract the cooling of a layer being printed, devices maybe used to increase the temperature of the surrounding air in earlierprinting systems. By contrast, embodiments of the disclosure may depositmaterial at a high enough speed so that it is not necessary to slow thenatural cooling process by heating surrounding air. Indeed, in someembodiments of the disclosure, cooling devices, e.g., fans, may be usedto cool the temperature of ambient air. Ambient air in embodiments ofthe disclosure may therefore range between, for example, 65-85° F.,which may be cooler than ambient air in prior systems. In embodiments ofthe disclosure, only the print head may generate heat to melt flowablematerial. Accordingly, by allowing the part to be printed at ambienttemperature, a previously deposited layer of print bead may naturallycool to the proper temperature as the next layer of material is beingdeposited, so that the process may be continuous.

Moreover, aspects of the disclosure may include a machine that requiresless floor space than two separate machines, may not require movement ofthe printed part for machining, may machine location marks for alignmentinto the printed part if the printed part is to be moved, and/or mayprint and trim at the same time on the same machine.

Aspects of the present disclosure relate to apparatus and methods tofabricate parts that may be printed at ambient temperature(s), ratherthan in a heated environment or on a heated worktable, using a muchlarger print bead at a high enough speed that, through natural cooling,each previously printed layer may cool to a proper temperature as a nextlayer is printed or deposited. The printed layer may be cool enough sothat it has hardened sufficiently to support the next layer withoutdistorting, but may also be warm enough to fuse adequately with the nextdeposited layer of printed material. Thus, there may be an optimaltemperature range for printing fully fused, quality parts. For example,some polymers, e.g., an Acrylonitrile-Butadiene-Styrene (ABS) polymer,may bond with a previously printed layer of material when it is printedat a temperature range of between approximately 100-135° C. It isacknowledged, however, that different polymers may appropriately bondwith previously printed layers when those polymers printed at differenttemperature ranges.

The present disclosure describes a machine that may be large and robustenough to accept and move a large extruder (e.g., a large plasticextruder), including supporting equipment, at a high enough speed inorder to print (or deposit) the largest layer of a flowable material(e.g., a thermoplastic material) desired in the time available, asdictated by natural cooling. Also, the extruder may be large enough tohave a high enough throughput to print the largest layer of flowablematerial desired within the time available, as dictated by naturalcooling. In some aspects, the extruder and print head may be configuredto move in three dimensions, as opposed to moving the associatedworktable, in order to achieve layer-to-layer vertical motion. In orderto facilitate making the printing process continuous, the machine maycontain a manual control actuator, e.g., a knob, button, switch, orlever, on the print control to allow an operator to speed up or slowdown the speed of the print process. To further assist the operator, athermographic camera system may be located on or adjacent to themachine, which may display the temperature of the layer being printed,the temperature of the material being output from nozzle 51, and/or thetemperature of the material in the extruder output.

Since the time required for a particular thermoplastic material to coolfrom print temperature to the proper temperature to accept the nextlayer may be relatively consistent (assuming, e.g., that ambienttemperature is relatively consistent), an alternative approach may bepossible. In this approach, the operator may input the desired coolingtime into the print control, and the print control may adjust the printfeed speed so that it may require that amount of time to print eachlayer in order to keep the print process continuous.

The machine may also include a print gantry, which may further includean extruder larger in size than an extruder that may be used in standard3D printing or additive manufacturing machines. This larger extruder maybe operated using a servomotor and gearbox arrangement, as well as amelt pump (also referred to as a gear pump or a polymer pump), which maybe attached to the extruder. In some embodiments, the melt pump mayinclude a set of meshed gears located within a housing. The melt pumpmay also operate with a servomotor and gearbox. The large extruder mayinclude an applicator head, which may be attached below the melt pump,and may further include an attached compression roller, which may beoperated by a servomotor. Several servomotors may also be included withthis machine, along with associated gearboxes, in order to permit theextruder to move in three dimensions (e.g., along the x-, y-, andz-axes). The machine may also include a trimming gantry, which mayconsist of a large router motor and several servomotors with associatedgearboxes to permit the trimming gantry to move in three dimensions, aswell as to rotate about two different axes. Both printing and trimminggantries may be fixed to a worktable in order to allow the machine toprint a part and trim that part on the same worktable. By incorporatingthe printing and trimming gantries on the same worktable, less floorspace may be used as opposed to having two separate machines (e.g.,separate printing and trimming machines) on a manufacturing floor.

By using a common worktable that may not move, a printed part may notneed to be moved to a separate trimming machine for trimming of theprinted part to occur. The trimming gantry may be attached to alarge-scale additive manufacturing machine, which may allow the part tobe trimmed in the same location as it was printed. If an operator doeswant to move a printed and/or trimmed part off of the machine, locationmarks may be machined into the part prior to moving it. These locationmarks may be used later when needing to realign the part to a machine'scoordinate system. For example, the part may be printed and then trimmedat a later time on the same machine or on a different machine, ifdesired, yet with the inclusion of the location marks, the part may beeasily and quickly aligned.

The machine may also print a part on one side of a worktable, while atthe same time the machine may trim a printed part on the other side ofthe table by using a reservation system. The reservation system mayreserve space for each printing and trimming gantry to ensure that eachgantry does not interfere with the other. In addition, a high-walldesign may be incorporated into the machine to enclose the printing andtrimming operations. The high-wall design may enclose dust and fumesgenerated during the printing and/or trimming process. The machine mayalso include a dust and fume extraction system to remove any unwantedprinting fumes and/or trimming dust during and/or after printing andtrimming. The dust and fume extraction system may be part of thehigh-wall design.

Embodiments of the present disclosure may be drawn to additivemanufacturing systems. An additive manufacturing system may include anextruder having an opening dimensioned to receive a material. Theadditive manufacturing system may also include an extruder output influid communication with the extruder, wherein the extruder output mayextend away from the extruder along a longitudinal axis. The additivemanufacturing system may also include one or more heaters positionedalong at least a portion of the extruder output. As the material passesthrough the extruder output, the one or more heaters may at leastpartially melt the material. The additive manufacturing system may alsoinclude a gear pump in fluid communication with the extruder output forreceiving the at least partially melted material. The additivemanufacturing system may also include a nozzle in fluid communicationwith the gear pump for depositing the at least partially meltedmaterial.

The present disclosure may be drawn to additional exemplary embodimentsof an additive manufacturing system. An additive manufacturing systemmay include an extruder having an opening dimensioned to receive amaterial. The additive manufacturing system may also include an extruderoutput fluidly connected to the extruder for receiving the material fromthe extruder, wherein the extruder output may extend from the extruderalong a longitudinal axis. The additive manufacturing system may alsoinclude one or more heaters operably coupled to the extruder output forheating the extruder output, wherein as the material passes through theextruder output, the one or more heaters may at least partially melt thematerial. The additive manufacturing system may also include a nozzle influid communication with the extruder output for depositing the materialonce the material is at least partially melted. The additivemanufacturing system may also include an actuator for adjusting thespeed of the material through at least a portion of the additivemanufacturing system. The additive manufacturing system may also includea temperature sensor and an indicator configured to communicate to anobserver a temperature of the at least partially melted material, e.g.,material in extruder output 61, material being deposited by nozzle 51,and/or a layer of material once deposited by nozzle 51.

Embodiments of the present disclosure may be drawn to additivemanufacturing methods for forming a part. The method may includereceiving a material into an opening of an extruder of the machine. Themethod may also include heating the material as it passes through anextruder output fluidly connected to the extruder to at least partiallymelt the material. The method may also include outputting the materialfrom a nozzle in fluid communication with the extruder output to form aportion of the part. The method may also include adjusting a speed ofmovement of the material through the machine in response to input froman operator. The method may also include determining a temperature ofthe material output from the nozzle. The method may also includedisplaying the temperature of the material output from the nozzle.

As used herein, the terms “comprises,” “comprising,” or any othervariation thereof, are intended to cover a non-exclusive inclusion, suchas a process, method, article, or apparatus. The term “exemplary” isused in the sense of “example,” rather than “ideal.” As used herein, theterm “long” will refer to a component having one dimension that islarger than the other dimensions and encompasses long, tall, wide, etc.

It may be understood that both the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not restrictive of the disclosure, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein, and constitutea part of this specification, illustrate exemplary aspects of thepresent disclosure and together with the description, serve to explainthe principles of the disclosure.

FIG. 1 is a perspective view of an exemplary CNC machine for formingarticles in an additive manufacturing process, according to an aspect ofthe present disclosure;

FIG. 2 is an enlarged perspective view of an exemplary carrier andextruder of the exemplary CNC machine shown in FIG. 1;

FIG. 3 is an enlarged perspective view of an exemplary carrier andapplicator head assembly of the exemplary CNC machine shown in FIG. 1;

FIG. 4 is an enlarged cross-sectional view of an exemplary applicatorhead assembly of the exemplary carrier shown in FIG. 3, during use; and

FIG. 5 is a flow-chart depicting steps of an exemplary method, accordingto an aspect of the present disclosure.

DETAILED DESCRIPTION

The present disclosure is drawn to, among other things, methods andapparatus for fabricating components via additive manufacturing, suchas, e.g., 3D printing. Specifically, embodiments of the disclosure maybe drawn to a machine that deposits (e.g., prints) at an ambienttemperature, rather than in a heated environment. Exemplary machines mayachieve this by using a larger print bead than is typically used inadditive manufacturing output at a sufficiently high speed so thatlayers of deposited material may be naturally cooled to the propertemperature just as a subsequent layer of material is being deposited.This may allow the printing process to be continuous. Embodiments of thedisclosure may also require less floor space than two separate machines,may not require the printed part to be moved for machining, may machinelocation marks for alignment into the printed part if the printed partmay be moved, and/or may print and trim at the same time on the samemachine.

For purposes of brevity, the methods and apparatus described herein willbe discussed in connection with the fabrication of parts fromthermoplastic materials. However, those of ordinary skill in the artwill readily recognize that the disclosed apparatus and methods may beused with any flowable material suitable for additive manufacturing.

With reference now to FIG. 1, there is illustrated a CNC machine 1embodying aspects of the present disclosure. A controller (not shown)may be operably connected to CNC machine 1 for displacing an applicationnozzle 51 along a longitudinal line of travel (x-axis), a transverseline of travel (y-axis), and a vertical line of travel (z-axis), inaccordance with a program inputted or loaded into the controller forperforming an additive manufacturing process to form a desiredcomponent. In some examples, the program may be inputted or loaded intothe computer for forming 3D printed components of a desired size and/orshape. CNC machine 1 may be configured to print or otherwise build 3Dparts from digital representations of the 3D parts (e.g., AMF and STLformat files) programmed or loaded into the controller.

For example, in an extrusion-based additive manufacturing system, a 3Dpart may be printed from a digital representation of the 3D part in alayer-by-layer manner by extruding a flowable material. The flowablematerial may be extruded through an extrusion tip or nozzle 51 carriedby a print head or applicator head 43 of the system. The flowablematerial may be deposited as a sequence of beads or layers on asubstrate in an x-y plane. In some examples, the x-y plane may be usedfor printing long parts without increasing the height of the machine.The extruded, flowable material may fuse to a previously depositedmaterial and may solidify upon a drop in temperature. The position ofthe print head relative to the substrate may then be incrementallyadvanced along a z-axis (perpendicular to the x-y plane), and theprocess may then be repeated to form a 3D part resembling the digitalrepresentation.

CNC machine 1, shown in FIG. 1, includes a bed 20 provided with a pairof transversely spaced side walls 21 and 22, a printing gantry 23, and atrimming gantry 36 supported on opposing side walls 21 and 22, acarriage 24 mounted on printing gantry 23, a carrier 25 mounted oncarriage 24, an extruder 61, and an applicator assembly 43 mounted oncarrier 25. Located on bed 20 between side walls 21 and 22 is ahorizontal worktable 27 provided with a support surface. The supportsurface may be disposed in an x-y plane and may be fixed or displaceablealong an x-axis and/or a y-axis. For example, in a displaceable version,horizontal worktable 27 may be displaceable along a set of rails mountedon bed 20. Displacement of horizontal worktable 27 may be achieved usingone or more servomotors and one or more rails (not shown) mounted on bed20 and operatively connected to horizontal worktable 27.

Printing gantry 23 and trimming gantry 36 are disposed along a y-axis,supported on walls 21 and 22. In FIG. 1, printing gantry 23 and trimminggantry 36 are mounted on a set of guide rails 28, 29, which are locatedalong a top surface of side walls 21, 22. Printing gantry 23 and/ortrimming gantry 36 may either be fixedly or displaceably mounted, and,in some aspects, printing gantry 23 and trimming gantry 36 may bedisposed along an x-axis. Printing gantry 23 and trimming gantry 36 maybe displaceable by a set of servomotors (not shown) mounted on printinggantry 23 and trimming gantry 36 and operatively connected to tracks,e.g., guide rails 28, 29, provided on side walls 21 and 22 of bed 20. Inan exemplary displaceable version, one or more servomotors may controlmovement of either printing gantry 23 and/or trimming gantry 36.

Carriage 24 is supported on printing gantry 23 and is provided with asupport member 30 mounted on and displaceable along one or more guiderails 31, 32, and 33 provided on printing gantry 23. Carriage 24 may bedisplaceable along a y-axis on one or more guide rails 31, 32, and 33 bya servomotor mounted on printing gantry 23 and operatively connected tosupport member 30. Carrier 25 is mounted on one or more verticallydisposed guide rails 34, 35 supported on carriage 24 for displacement ofcarrier 25 relative carriage 24 along a z-axis. Carrier 25 may bedisplaceable along the z-axis by a servomotor (not shown) mounted oncarriage 24 and operatively connected to carrier 25. In someembodiments, guide rails (not shown) may be located adjacent bed 20 oralong the sides of bed 20.

As best shown in FIG. 2, mounted to carrier 25 is an extruder 61, whichmay be larger than extruders used for standard 3D printing. Extruder 61may be capable of extruding a flowable material (e.g., thermoplasticmaterial) at a rate of about 110 pounds per hour up to 500 pounds perhour, allowing for a significantly faster printing rate. Extruder 61 maybe large enough and may allow for a high enough throughput of flowablematerial to print the largest layer desired within a period of timepermitted by the flowable material's natural cooling properties.

A screw (not shown) may be disposed within an extruder tube 42 ofextruder 61. The screw may be actuated, or driven, by a servomotor 38,which may be operatively connected to the screw via a gearbox 39. One ormore heaters 41 may surround at least a portion of extruder tube 42, asshown. In some embodiments, heaters 41 may wrap around a circumferenceof extruder tube 42. Heaters 41 may be disposed along a portion or alongthe entire length of tube 42.

Pellets of material may be introduced into a supply opening 40 ofextruder tube 42. Those of ordinary skill will recognize that thepellets may be of any suitable material, for example, thermoplasticmaterial. The material may also be delivered to extruder tube 42 in anysuitable size or configuration, in addition to, or instead of, pellets.In an exemplary embodiment, the pellets introduced into extruder tube 42may be heated by the friction generated from rotation of the screwand/or by one or more heaters 41 disposed along the length of extrudertube 42. In an exemplary embodiment, once the pellets have melted, themolten material may be forced under pressure by the screw further intoextruder tube 42 and out of a bottom opening (not shown) of extruder 61.The molten material may be delivered to nozzle 51 for use in 3D printingactivities, as described above.

As best shown in FIG. 3, also mounted to carrier 25 (e.g., fixedlymounted to the bottom of carrier 25) is a positive displacement gearpump 74, which may be driven by a servomotor 75, through a gearbox 76.Gear pump 74 receives molten plastic from extruder 61, shown in FIG. 2.A bead shaping roller 59, for compressing material, may be mounted on acarrier bracket 47. Roller 59 may be movably mounted on carrier bracket47, for example, rotatably or pivotably mounted. Roller 59 may bemounted so that a center portion of roller 59 is aligned with nozzle 51.In some examples, roller 59 may be oriented tangentially to nozzle 51.In some examples, nozzle 51 may be sized larger than nozzles used instandard 3D printing. Roller 59 may be mounted relative to nozzle 51 sothat material, e.g., one or more beads of flowable material (such as alarger-than-average bead of thermoplastic resin), discharged from nozzle51 is smoothed, flattened, leveled, and/or compressed by roller 59. Oneor more servomotors 60 may be configured to move, e.g., rotationallydisplace, carrier bracket 47 via a pulley or sprocket 56 and drive-chainor belt 65 arrangement, or by any other suitable means.

Continuing with reference to FIG. 4, applicator head 43 may include ahousing 46 with a roller bearing 49 mounted therein. Carrier bracket 47may be fixedly mounted to an adaptor sleeve 50, journaled in bearing 49.As best shown in FIGS. 2-4, a conduit 52 may be used to convey anoversized molten bead of a flowable material (e.g., thermoplasticmaterial) under pressure from a suitable source (e.g., extruder 61 andan associated gear pump) disposed on carrier 25 to applicator head 43.Applicator head 43 may be fixedly (or removably) connected to, and incommunication with, a larger-than-normal nozzle 51. In use, flowablematerial 53 (e.g., melted thermoplastic) may be heated sufficiently toform a large or oversized molten bead thereof, which is then extrudedthrough conduit 52 and delivered through nozzle 51, to form rows ofdeposited material 53 on a surface of worktable 27. The rows depositedby the larger nozzle 51 may correspondingly be larger than normal.

Exemplary beads may range from approximately 0.1 inches thick toapproximately 0.5 inches thick, and from approximately 0.5 inches wideto approximately 1.5 inches wide. In one embodiment, a bead may beapproximately 0.20 inches thick and approximately 0.83 inches wide. Itis contemplated that exemplary beads may be larger, e.g., approximately0.5 inches thick and approximately 1.5 inches wide, or may be smaller,e.g., approximately 0.1 inches thick and approximately 0.5 inches wide.Smaller sized beads may constrain the size of the part that may beformed by depositing that bead, because smaller beads may cool quicker.

Such beads of molten material may be flattened, leveled, and/or fused toadjoining layers by any suitable means, such as, e.g., roller 59. Asdescribed above, successive layers may be deposited and fused to oneanother to form an article. In an exemplary embodiment, during operationof machine 1, each successive deposited (e.g., 3D printed) layer may notcool below the temperature at which proper layer-to-layer bonding occursbefore the next layer is deposited on the previous layer. The properbonding temperature may depend, e.g., on the type of polymer beingprinted. For example, when printing an ABS polymer, the temperature ofthe material may need to be at least approximately 100° C. for properbonding to occur. However, with other polymers, proper bonding mayrequire that the deposited material be hundreds of degrees higher.

The larger bead of flowable material used in embodiments of the presentdisclosure may contain more British Thermal Units (“BTUs”) of heat thana standard small bead. The amount of heat energy within a print bead isgenerally dependent on the cross-sectional size of the bead. Forexample, if the bead is twice as large, it will generally contain twiceas much heat energy, and if it is four times as large, it will generallycontain four times as much heat energy. Also, a smaller, thinner beadhas more surface area relative to its volume than a thicker bead, so thesmaller, thinner bead will generally cool faster than the thicker bead.The exact BTU value of a given bead may vary based on, e.g., the type ofpolymer being used and the dimensions/geometry of the polymer bead.

Owing to the greater BTUs of heat in the large bead of material, moreinternal heat may be transferred from the freshly printed large bead ofmaterial to the previous printed layer. This heat transfer to theprevious layer may allow the previously printed layer to cool more thannormal before the subsequent layer is printed. Even though the previouslayer is cooler, because of the greater BTUs of heat contained in thelarger print bead of the subsequent layer, the subsequent layer maysufficiently reheat the previously deposited layer of flowable matter tocreate an acceptable layer-to-layer bond between the layers. Because theprevious layer of deposited flowable material may be cooler, it may bein a relatively solid state prior to accepting the next layer ofdeposited material. Therefore, the overall part may be at a lowertemperature than if the part had to be printed in an elevatedtemperature in a heated environment. When an entire part printed in aheated environment is finally cooled, internal stresses may tend todevelop within the part, which may open undesirable voids in theinterior of the part. This tendency may be reduced or avoided if thepart is cooled, layer by layer, to a relatively solid state during theprinting process, as described above.

Exemplary machines of the present disclosure may be used to deposit aflowable material (e.g., print thermoplastic material) at a speed atwhich the material may cool to the proper temperature range in theamount of time it may require to print each layer. For example, a beadwith a thickness of approximately 0.2 inches and a width ofapproximately 0.83 inches may be deposited at a speed of between 75 and500 inches per minute, and a melt core of approximately 40 mm may beused. A larger melt core (consisting of a feed housing, an extruder, anda polymer melt pump), which may process more material, may operate atprint speeds of well over 1,000 inches per minute. In this way, theprinting and cooling process may be continuous. Machine 1 may includeone or more features to facilitate the continuity of this process. Insome embodiments, a manually controlled actuator (e.g., a knob, lever,switch, button, or other suitable component) (not shown) may be locatedon the print control of machine 1. The actuator may allow the operatorto speed up or slow down the speed of the print process. In other words,the operator may actuate the actuator to adjust the speed of depositionof flowable material.

Additional features in the control may allow the operator to maintain adesired dimension of deposited flowable material (e.g., a dimension ofthe printed bead of material) despite changes in machine speed.Exemplary embodiments may include a control that performs at least twooperations. First, the speed and path of machine 1 may be determined bya program being executed by the control, e.g., a CNC program. Anindependent process control, which operates independent of the CNCprogram, may monitor the speed at which machine 1 is moving and mayadjust the speed of gear pump 74 correspondingly to maintain the properbead dimension being deposited as the speed of machine 1 changes. Theindependent process control may also adjust the corresponding speed ofthe extruder feeding the melt pump. Embodiments of the disclosure mayalso include operator-adjustable “modifiers,” which may further adjustthe speed of gear pump 74 during periods of acceleration anddeceleration to further adjust for any compressibility of the materialbeing printed. This is because compressible materials may not react asquickly to changes in pump speed and so may need to be adjusted for.Embodiments may also include a separate manual control actuator, e.g., aknob, button, switch, or lever, which adjusts the ratio between thespeed of machine 1 and the output of gear pump 74, Changing this ratiomay change the width of the bead while flowable material is beingdeposited.

In some embodiments, machine 1 may include a velocimetry assembly (ormultiple velocimetry assemblies) configured to determine flow rates(e.g., velocities and/or volumetric flow rates) of material 53 beingdelivered from applicator head 43. The velocimetry assembly may transmitsignals relating to the determined flow rates to the aforementionedcontroller coupled to machine 1, which may then utilize the receivedinformation to compensate for variations in the material flow rates. Forexample, the velocimetry assembly may be used to control the thickness,or other suitable parameter, of the large or oversized bead of printed,flowable material.

In some embodiments, a thermographic camera system 64 (shown in FIG. 1),may be used to determine the temperature of material being deposited andmay display the temperature of the flowable material being printedduring the print process. Exemplary embodiments of machine 1 may bedesigned to operate at temperatures up to approximately 450° C. (825°F.). The particular print temperature used may depend, e.g., on the typeof flowable material being deposited. In some embodiments, materialsthat are deposited at a higher temperature may tend to cool faster andso may be capable of being deposited at a faster speed. The speed ofmaterial deposition may be determined at least in part by the coolingcharacteristics of the material being deposited and/or the length of thedeposited bead on each layer. For example, if a material cools from thetemperature upon deposition to the proper temperature for receiving thesubsequent later of material in a minute, and each layer is 200 incheslong, then the print speed will be 200 inches/minute.

For example, one or more display screens, lights, or other suitableaudio, visual, or haptic feedback indicators may be included inthermographic camera system 64 and/or on machine 1. In some embodiments,thermographic camera system 64 and/or machine 1 may include an indicatorthat allows the desired print temperature range and/or the actual printtemperature range to be displayed, e.g., in text or in a specific color.In some embodiments, a color, e.g., the color green, may be displayed tothe operator of machine 1 to indicate that the print process isoccurring within the desired temperature range. Thus, if the part startsto become too hot or too cool, the color may change, change intensities,or may cease to be shown, which may indicate to the operator that theprint process may need to be sped up or slowed down. Accordingly, theoperator may adjust the print rate, e.g., speed the print rate up, whichmay lead to reducing the cooling time and increasing the temperature ofeach layer of deposited material. If the part becomes too hot, thedeposition or print process may be slowed down, which may allowincreased cooling time between layers and cooling the part.

The time required for a particular thermoplastic material to cool fromprint temperature to the proper temperature to accept the next layer isrelatively fixed, because the properties of each thermoplastic materialused is known in advance of deposition. By knowing the required timeperiod, an alternative approach may be possible. In some embodiments,the operator may input the desired cooling time into the print control,and the operator or the print control may adjust the print feed speed sothat machine 1 may require the amount of time input to print each layer.The operator may then be free to adjust the layer print time during theprint process to allow for other variables at the operator's discretion.This approach may be desirable, e.g., for parts having a variablegeometry, since feed speed may need to be adjusted for the differentsized layers, which may be more difficult if done manually.

As shown in FIG. 1, trimming gantry 36 may be mounted on spaced sidewalls 21, 22 to perform trimming functions. Trimming gantry 36 may becontrolled by the control of machine 1, or trimming gantry 36 may becontrolled by a separate control unit. Printing gantry 23 and trimminggantry 36 may be mounted to worktable 27, which may allow machine 1 toprint parts on the same worktable 27 that trimming gantry 36 uses totrim the parts. Therefore, less floor space may be used compared tohaving two separate machines to perform printing and trimming operationsseparately.

Since machine 1 uses one common worktable 27, which may be fixedlymounted to machine 1, the desired part or article does not requiremovement to a different machine for the trimming operation. Trimminggantry 36 may allow the part to be trimmed in the same location as itwas printed or on another location of the same worktable. If an operatorof machine 1 desires to move a printed part off of worktable 27,location marks may be machined into the part prior to moving it. Indoing so, the location marks may be used later to realign the part to adifferent machine's coordinate system or to the same machine'scoordinate system. Location marks may permit a part to be printed on afirst machine and then trimmed at a later time on the same machine or ona different, second machine, if desired. Location marks may be used toeasily and quickly align the printed part on the same machine or on adifferent machine.

During operation, machine 1 may print a part on one side of worktable 27while at the same time trimming gantry 36 may trim a part on the otherside of worktable 27 using a reservation system. Printing and trimmingoperations may include separate programs inputted into separate,respective controls, or the same control may control both operations.When a program is started, a control may measure how much space isavailable on worktable 27 to work on a part. Based on the measurementmade by either control, the control that made the measurement may thencommunicate that information to the control that did not make themeasurement. For example, the control of printing gantry 23 may create afirst measurement and may forward that information to the control oftrimming gantry 36. In effect, a reservation process is created. Byreserving that worktable area for its own use, each of printing ortrimming gantries 23 and 36 may make optimal use of available space onworkable 27. If the operator then attempts to begin a program on eitherthe print control or the trim control, that control first determines ifthere is sufficient unreserved worktable area to process the program. Ifthere is sufficient unreserved worktable area, it begins either theprinting or trimming process. If there is insufficient unreservedworktable 27 area, the control informs the operator that there is notsufficient unreserved worktable 27 area available. Either control mayuse a display, or other suitable notification system, to inform theoperator of the unreserved workable 27 area.

In an exemplary embodiment, a high-wall design, which may include one ormore doors (not shown), may enclose the print and trim operations duringoperation of machine 1. Machine 1 may also include a dust and fumeextraction system 37, as shown in FIG. 1. In some embodiments, dust andfume extraction system 37 may be mounted on either or both of spacedside walls 21 or 22. Dust and fume extraction system 37 may direct airfrom the printing process through appropriate filters to remove fumescreated by the printing process. System 37 may also be used to removeairborne dust that may be created during the trimming process. System 37may also support one or more vacuum hoses, which may allow the operatorto vacuum up trim chips created during the trimming process.

FIG. 5 depicts an exemplary additive manufacturing method of forming apart using CNC machine 1. At a first step 502, opening 40 of extruder 61may receive an input material (e.g., thermoplastic pellets). At a nextstep 504, extruder 61 may be actuated to heat, in order to at leastpartially melt, the input material. As input material passes throughextruder tube 42 of extruder 61, input material may be heated byactuating one or more heaters 41, which surround extruder tube 42. Inputmaterial may also be heated by friction generated by rotation of thescrew disposed within extruder tube 42. The screw may be driven byservomotor 38, which may be operatively connected through gearbox 39.

Next, at a step 506, the input material may be output from nozzle 51.Nozzle 51 may be in fluid communication with extruder tube 42. Nozzle 51may be oversized to create a large deposit of flowable material (e.g.,one or more large thermoplastic print beads). Nozzle 51 may be used todeposit the melted input material (e.g., melted thermoplastic material).Further, at a step 508, an actuator may be adjusted by the operator ofmachine 1 to adjust the speed of the input material through the system.An exemplary actuator may be a manually controlled knob, lever, switch,or button mounted to CNC machine 1.

Next, at a step 510, a temperature of the input material output fromnozzle 51 may be determined. In some embodiments, a temperature sensormay be used to determine the temperature of material output from nozzle51, for example, the temperature sensor may comprise a thermometer,thermistor, thermocouple, or any other suitable sensor. In someembodiments, the temperature may be determined using one or morethermographic cameras.

One of ordinary skill in the art will recognize that steps 506, 508, and510 may be performed in any particular order (e.g., the speed may beadjusted prior to output of material from nozzle 51 or the temperaturemay be determined prior to adjusting the speed). It is also acknowledgedthat steps may occur simultaneously with one another or may be ongoingthroughout the process (e.g., material may be output from nozzle 51 asthe speed is being adjusted or as the temperature of the output materialis being determined).

At a last step 512, the determined temperature may be displayed to theoperator of machine 1. The temperature displayed may be the temperatureof the input material as it is output from nozzle 51 and may be providedto the operator. The temperature may alternatively or additionally bethe temperature of partially melted input material as it passes throughextruder tube 42. In some embodiments, the temperature may be displayedon any suitable screen or display device incorporated as part of orremovably or fixedly mounted to CNC machine 1 and/or a thermographiccamera system 64. In some embodiments, an indicator or other suitabledevice may be configured to communicate to an operator (e.g., observedby the operator) the temperature obtained at step 512. Other suitabledevices may include one or more display screens, lights, or othersuitable audio, visual, or haptic feedback indicators. The one or moreindicators may be included in thermographic camera system 64 and/or onmachine 1.

While steps 502-512 are depicted in a particular order, the principlesof the present disclosure are not limited to the order depicted in FIG.5. Further, any of steps 502-512 may occur simultaneously and/or may berepeated two or more times during operation of machine 1.

In the course of fabricating a component pursuant to the methodsdescribed herein, the control system of CNC machine 1, in executing theinputted program, may operate the several servomotors as described todisplace printing gantry 23 and/or trimming gantry 36 along the x-axis,displace vertical worktable along the x-axis, displace carriage 24 alongthe y-axis, displace carrier 25 along the z-axis, and rotate bracket 47about the x-axis thereof, in accordance with the inputted program, toprovide the desired end product or a near duplicate thereof. In someexamples, bracket 47 may carry roller 59 so that when roller 59 isrotated from printing on a horizontal plane to printing on a verticalplane, roller 59 changes from rotating about the z-axis to rotatingabout the x-axis.

While principles of the present disclosure are described herein withreference to illustrative embodiments for particular applications, itshould be understood that the disclosure is not limited thereto. Thosehaving ordinary skill in the art and access to the teachings providedherein will recognize additional modifications, applications,embodiments, and substitution of equivalents all fall within the scopeof the embodiments described herein. Accordingly, the inventionsdescribed herein are not to be considered as limited by the foregoingdescription.

What is claimed is:
 1. An additive manufacturing system, comprising: anextruder having an opening dimensioned to receive a material; anextruder output in fluid communication with the extruder, wherein theextruder output extends away from the extruder along a longitudinalaxis; one or more heaters positioned along at least a portion of theextruder output, wherein as the material passes through the extruderoutput, the one or more heaters at least partially melt the material; agear pump in fluid communication with the extruder output for receivingthe at least partially melted material; a thermographic camera directedto measure a temperature of the at least partially melted material asthe at least partially melted material passes through the extruderoutput and before the at least partially melted material passes throughthe gear pump; a controller operably connected to the thermographiccamera; a nozzle in fluid communication with the gear pump fordepositing the at least partially melted material; and amanually-controllable actuator connected to the controller andconfigured to cause the controller to increase or decrease a speed atwhich the at least partially melted material is deposited by the nozzleso as to increase or decrease a cooling time of layers of a partdeposited by the additive manufacturing system, wherein the controlleris further configured to generate a notification indicative of whetherthe speed at which the at least partially melted material is depositedshould be changed based on the temperature.
 2. The system of claim 1,further comprising a screw extending within the extruder output.
 3. Thesystem of claim 2, wherein rotation of the screw within the extruderoutput is configured to generate heat sufficient to at least partiallymelt the material when the material is within the extruder output. 4.The system of claim 1, wherein the one or more heaters includes aplurality of heaters disposed along a length of the extruder output. 5.The system of claim 1, further comprising a display, wherein the displayis configured to indicate to an operator the temperature of the at leastpartially melted material.
 6. The system of claim 1, wherein theadditive manufacturing system includes a programmable computer numericcontrol machine.
 7. An additive manufacturing system, comprising: anextruder having an opening dimensioned to receive a material; anextruder output fluidly connected to the extruder for receiving thematerial from the extruder, wherein the extruder output extends from theextruder along a longitudinal axis; one or more heaters operably coupledto the extruder output for heating the extruder output, wherein as thematerial passes through the extruder output, the one or more heaters atleast partially melt the material; a nozzle in fluid communication withthe extruder output for depositing the material once the material is atleast partially melted; a manually-controllable actuator for adjusting aspeed of the material through at least a portion of the additivemanufacturing system; a gear pump in fluid communication with theextruder output for receiving the at least partially melted material; atemperature sensor; an indicator configured to communicate to anobserver a temperature of the at least partially melted material, thetemperature being indicative of a current temperature of the at leastpartially melted material as the at least partially melted materialpasses through the extruder output and before the at least partiallymelted material reaches the gear pump; and a controller operablyconnected to a thermographic camera and the manually-controllableactuator, wherein the controller is configured to increase or decrease aspeed at which the at least partially melted material is deposited bythe gear pump in response to an interaction with themanually-controllable actuator so as to increase or decrease a coolingtime of layers of a part deposited by the additive manufacturing system,wherein the controller is further configured to generate a notificationindicative of whether the speed at which the at least partially meltedmaterial is deposited should be changed based on the temperature.
 8. Thesystem of claim 1, further comprising: first and second side wallssupporting a first gantry and a second gantry, wherein the first andsecond side walls are spaced apart from each other in a first direction,and wherein the first gantry and the second gantry are horizontallyspaced apart from each other in a second direction that is orthogonal tothe first direction; said extruder, said extruder output, and said oneor more heaters being supported by the first gantry; wherein the secondgantry is configured to perform trimming on the part printed by anapplicator head that supports the nozzle; and wherein the first gantryand the second gantry are each displaceable by respective servomotors.9. The system of claim 7, further comprising a screw extending withinthe extruder output, wherein rotation of the screw within the extruderoutput is configured to generate heat to at least partially melt thematerial within the extruder output.
 10. The system of claim 7, whereinthe temperature sensor includes the thermographic camera.
 11. The systemof claim 7, wherein the controller is configured to adjust a speed ofmaterial received by the opening of the extruder.
 12. The system ofclaim 7, wherein the additive manufacturing system includes aprogrammable computer numeric control machine.
 13. An additivemanufacturing system, comprising: first and second side walls supportinga first gantry and a second gantry wherein the first and second sidewalls are spaced apart from each other in a first direction, and whereinthe first gantry and the second gantry are horizontally spaced apartfrom each other in a second direction that is orthogonal to the firstdirection; an extruder supported on the first gantry and having anopening dimensioned to receive a material and an output that extendsaway from the extruder along a longitudinal axis; a nozzle in fluidcommunication with the extruder for depositing the material, the secondgantry being configured to perform trimming on a part printed by anapplicator head that supports the nozzle; a thermographic cameradirected to measure a temperature of the material as the material isdeposited; a controller operably connected to the thermographic camera;and a manually-controllable actuator connected to the controller andconfigured to cause the controller to increase or decrease a speed atwhich the material is deposited by the nozzle so as to increase ordecrease a cooling time of layers of a part formed by the additivemanufacturing system, wherein the controller is further configured togenerate a notification indicative of whether the speed at which thematerial is deposited should be changed based on the temperature. 14.The system of claim 13, wherein the first gantry and the second gantryare each displaceable by respective servomotors.
 15. The system of claim13, further including a worktable extending between the first gantry andthe second gantry.
 16. The system of claim 13, wherein the thermographiccamera is configured to measure the temperature of the material as thematerial is deposited from the nozzle.
 17. The system of claim 1,wherein the controller is further configured to increase or decrease thespeed at which the at least partially melted material is deposited bythe nozzle based on a layer print time.
 18. The system of claim 7,wherein the controller is further configured to increase or decrease thespeed at which the at least partially melted material is deposited bythe nozzle based on a layer print time.
 19. The system of claim 13,wherein the controller is further configured to increase or decrease thespeed at which the material is deposited by the nozzle based on a layerprint time.
 20. The system of claim 1, wherein the controller is furtherconfigured to increase or decrease the speed at which the at leastpartially melted material is deposited by the nozzle based on a coolingtime associated with the material.